Re: Leaving the Dojo
1. Is leaving his old sensei justifiable?
Indeed. We must all make our own decisions in life, even in the arts. Leaving without a word to his Sensei in my opinion is rather rude. But sometimes people do not want to confront others, especially when they know it may bother that person. But he may find that, the Sensei really does appreciate him, and there were other reasons why the promotion has not taken place. This may help in the growth of the student to approach the Sensei.
2. Should he approach his old sensei and tell him the truth or leave and tell lies about the real reason for his leaving?
Approach. Once can not achieve greatness in spirit by lying and deceiving. I know that sounds awfully spiritual, but to leave unfinished business in the arts bother people sometimes as well for long periods of time. The Sensei has passed down knowledge to this student, taken the time to show the student things he has learned, the least the student could do is approach and tell the truth.
3. Can he do his resignation in writing or better personal?
If it is that big of a deal I suggest writing it out on an e-mail or something, and then maybe meeting in person.
-I have done this before. I left an Isshin Ryu Karate Sensei because I felt I wasn't progressing or learning enough. I approached him and discussed why I was leaving. I think I had been there only a mere six months.
He was angry about it. He went off on me, telling me how much I had learned and how much I had progressed etc etc. He then told me that I wouldn't find another place to train in that area (Sierra Vista, AZ) that I could learn any more than what he was talking, etc etc.
Needless to say I ended up finding a Jujitsu instructor that was teaching out of his garage and I ended up helping him teach at his first official dojo years later.
I thought I would show my experience with quitting in case you wanted to know if anyone else has gone through what you are asking about. I have... It's a weird predicament to be in, and I only trained for six months.